Re: [Linux-cluster] GFS + DRBD Problems

From: Lon Hohberger <lhh redhat com>

To: linux clustering <linux-cluster redhat com>

Subject: Re: [Linux-cluster] GFS + DRBD Problems

Date: Mon, 03 Mar 2008 11:14:39 -0500

On Mon, 2008-03-03 at 11:23 +0000, gordan bobich net wrote:
> I have a 2-node cluster with Open Shared Root on GFS on DRBD.
Last week, I saw a car with a license plate from 'Wyoming'. Now,
someone's running GFS on shared root DRBD. My world's turning upside
down.
> A single
> node mounts GFS OK and works, but after a while seems to just block for
> disk. Very much as if it started trying to fence the other node and is
> waiting for acknowledgement.
If CMAN was trying to fence, you'd see it in /var/log/messages. I'm not
sure about DRBD.
> There are no fence devices defined (so this
> could be a possibility),
Unlikely. Even if this was the cause, you'd still see it (and you could
work around it).
> Unfortunately, it doesn't end there. When an attempt is made to dual-mount
> the GFS file system before the secondary is fully up to date (but is
> connected and syncing), the 2nd node to join notices an inconsistency, and
> withdraws from the cluster. In the process, GFS gets corrupted, and the
> only way to get it to mount again on either node is to repair it with
> fsck.
Off the top of my head, this sounds like a DRBD thing. If sync's
completed, it works, right?
-- Lon